A rotary-wing aircraft such as manned and unmanned helicopters is conventionally configured to include a fuselage which includes one main rotor (main rotary-wing) system charging lift and thrust, an engine providing a rotary power, and a transmission transferring a rotary power and one tail rotor (tail rotary-wing) system determining directivity by offsetting a torque generated by a rotation of the main rotor.
In the case of a helicopter having a twin engine or at least three engines, even though one engine fails, convention on international civil aviation forcibly regulates a horizontally forward flight of the helicopter using the remaining one or two engines for a predetermined time in terms of minimum safety. However, in the case of the conventional helicopter having a single engine, when the helicopter is in a non-powered state due to an engine failure, the helicopter may not perform the horizontally forward flight and therefore has a difficulty in an emergency landing.
As the related art to solve the above problem, there is U.S. patent Ser. No. 05/836,544 (Nov. 17, 1998) entitled “Emergency soft-landing system for rotor-type aircraft”.
The related art discloses an apparatus which provides lift for safe emergency landing by deploying parachutes from a front cockpit part and a rear tail wing when the helicopter having the single engine fails.
However, the apparatus according to the related art may deploy the parachutes only in the state which the main rotor of the helicopter is not rotated. The reason is that when the parachutes are deployed in the situation such as autorotation in which the main rotor is in a non-powered state, a secondary accident due to tangling of a parachute cord may be prevented. Therefore, the apparatus may be restrictively used only in extreme situations such as an engine stop, a main rotor stop, and a tail rotor stop.
Further, a posture of the helicopter may be safely maintained only when the parachutes are simultaneously deployed. When any one of the parachutes is deployed, a weight is concentrated on one side and thus the cockpit having a heavy weight may first collide with a ground.
Further, it is substantially impossible to induce the lift for the safe emergency landing by deploying the parachutes and to control a direction and a speed of the helicopter for the emergency landing, such that the helicopter may not make a safe landing with escaping a downtown such as a densely populated area, a mountainous terrain, and the like.